Kirk Frameworks

[572cv]

Nice cat picture ;-) That'll get things well along towards a million!

Really, thank you for your consistently engaging and thoughtful contributions here, for the terrific eye candy, and for my remarkable rides on Kirk.

[brewsmith]

Thanks for all your hard work and input on the forums Dave. Cheers from two of your kids living here in Denver (2015 v 2021)

[soulspinner]

It is your remarkable humility at the top of so many peoples list as one of THE best that is such a breath of fresh air. Thanks for your forum time too. It helps us understand what we ride and how that translates to our experience. Chapeau Mr Kirk.

[David Kirk]

Whelp - I finally have my new MRB (Montana Road Bike) built and ready to ride. The supply chain issues, combined with my lack of spare time, made this bike a long time in coming.

This frameset is 100% stainless steel and silver. I toyed with making a steel version instead of stainless but in the end opted to go stainless so that the fillets could be shown raw without any paint.

Now that photos are taken I can ride it - see you later....I'm clocking out and going for a ride.

dave

[lavi]

Amazing!

[Toddtwenty2]

This is one of my favorite bikes - ever. I need to leave this thread before my stable looks like Brewsmith's.

[herb5998]

Looks incredible Dave! glad you had some good weather to get it on the road.

[David Kirk]

Originally Posted by herb5998

Looks incredible Dave! glad you had some good weather to get it on the road.

I got very lucky with the timing and weather. I wrapped up the build yesterday, took photos this morning, rode it for about 90 minutes this afternoon and the snow arrives this weekend.

It's a really fun ride. The big tires roll along very well on pavement and don't feel slow or ponderous in any way and then when you leave the pavement behind it floats so well and you can just hammer along and the bike holds its line even in the loose/deep stuff.

And of course the tires combined with the butter smooth frame and fork and it feels a bit like it's cheating.

There's going to be a few hours of non-windy and non-snowy weather in the morning so maybe I'll get out again.

dave

[merckx]

Your machine looks fabulous, Dave. Nice work!

[roguedog]

Saw this on "the 'gram" (I feel soo cool) too.

Such a gorgeous machine. Love the stainless raw look. Such purity of form and function

Would love to understand how you evaluate this.

Like what's your checklist or what questions are you answering as you test this set up?

How do you differentiate the tubes from the geo?
Did you change the geo to fit the bike's purpose or to adjust for something else you're testing?
How do you extrapolate this to other sizes or maybe the question is.. how does this testing help inform when you might want to/need to use this tubeset for a customer?

[madsciencenow]

Looks fantastic, Dave!


Sent from my iPhone using Tapatalk

[David Kirk]

Those are damn good questions - thanks for asking.

There’s a few levels of evaluation and the higher the level the arguably more subjective the answers can be.



- level one - this is purely a house keeping thing. Is the cable routing simple and good so that the cables run clean and don’t rattle? Is there enough tire clearance so that when sprinting/climbing hard out of the saddle that the tire won’t rub the stays…and that the rim won’t rub the brake pads. Is there proper clearance for both a 1x and 2x chain ring set up? You get the idea. The higher level stuff won’t matter if the tire rubs the frame or fork of the brake cable rattles and annoys.



- level two - this could be generally looked at as stiffness. And this could be that the frame is either too stiff, too soft, or just right. I look for this stiffness in three primary areas - the drivetrain (what some call bottom bracket stiffness), torsional stiffness, and stiffness under hard braking. To a certain extent getting all three of these right is a matter of picking the proper diameter and wall thickness of the tubes used. This should be a fairly well trodden path but looking at the tube choices some make given the use of the bike and the size/weight of the rider makes me think it might not be.

The proper BB stiffness is generally pretty easy to get with the chainstay choice. Torsional stiffness is something many don’t talk about but it’s the key to get good handling. If the frame twists too much it will handle like crap…there’s little downside to having the frame stiffer than need be in torsion but if it’s been made too stiff there’s a good chance that the frame is heavier than it should be or that the ride will be harsh.

Braking stiffness is super important. If the fork is too soft and you grab a big handful of brake life can get overly exciting with chatter and/or funny handling due to the variable rake from flexing rearward.



- level three - this one is hugely subjective. Does the bike feel good to ride? Is it fun? Does it feel secure and stable while not being dead or boring in feel? Is the bike quiet feeling to your body and to the ear. Does the design encourage the me to take the long way home so that they get a bit more time on it? Does it have that wonderful ’snap’ when you get up to crest a roller out of the saddle. Does the steering feel right both in and out of the saddle? Can you sit up and open a Clif bar? Does the bike steer and handle intuitively on the surface it’s designed for? And do you find that when you end the ride that you lean it against the wall and as you walk away can’t resist turning back and taking one last look at it before food and a shower.



In the end I aim to please myself. If after all this time I like the bike that’s saying something. There’s been a crap-load of bikes over the past 30 years that I wanted to love but didn’t. It’s a bummer in that moment but it’s also a wonderful learning opportunity. But at the end of the day I think that if I like it that others will too. They might not know why and that matters little really. I know that I can design a bike for someone else that is a different size and weight than I am by picking the right tube….and when combined with the right fit and feel I feel confident that they will enjoy their bike as I enjoy mine.


I hope that makes sense.

Dave

Originally Posted by roguedog

Saw this on "the 'gram" (I feel soo cool) too.

Such a gorgeous machine. Love the stainless raw look. Such purity of form and function

Would love to understand how you evaluate this.

Like what's your checklist or what questions are you answering as you test this set up?

How do you differentiate the tubes from the geo?
Did you change the geo to fit the bike's purpose or to adjust for something else you're testing?
How do you extrapolate this to other sizes or maybe the question is.. how does this testing help inform when you might want to/need to use this tubeset for a customer?

[phishrabbi]

I suspect that a MRB would be a vast selling "model-" I'm sorely tempted to call and begin the process of ordering one myself.

I'd also suggest that you demonstrate that the bike could take the knobby version of the RH 38mm "Barlow Pass", the "Stellacoom"

I've run both, and while the Barlow Pass handles gravel acceptably, the Stellacoom gives significantly more traction in the loose stuff while giving up shockingly little on tarmac.

[roguedog]

Thanks for the detailed breakdown, Dave.

I think level two is where much of the framebuilder's experience comes into play. Seems there a lot of grey area in there; a lot to play with in there to try to discern the reasons for the bike's manners. Hmm.. and perhaps this is where the framebuilder's signature feel comes in? How do they want the bike to feel and handle will influence how they put together and select the tubes.

I feel like this where the framebuilder is a bit like Ollivander from Harry Potter. I was just trying to get some insight into how a framebuilder makes the jump from understanding what the customer wants/needs with how to and where to put together some tubes.

Originally Posted by David Kirk

Those are damn good questions - thanks for asking.

There’s a few levels of evaluation and the higher the level the arguably more subjective the answers can be.



- level one - this is purely a house keeping thing. Is the cable routing simple and good so that the cables run clean and don’t rattle? Is there enough tire clearance so that when sprinting/climbing hard out of the saddle that the tire won’t rub the stays…and that the rim won’t rub the brake pads. Is there proper clearance for both a 1x and 2x chain ring set up? You get the idea. The higher level stuff won’t matter if the tire rubs the frame or fork of the brake cable rattles and annoys.



- level two - this could be generally looked at as stiffness. And this could be that the frame is either too stiff, too soft, or just right. I look for this stiffness in three primary areas - the drivetrain (what some call bottom bracket stiffness), torsional stiffness, and stiffness under hard braking. To a certain extent getting all three of these right is a matter of picking the proper diameter and wall thickness of the tubes used. This should be a fairly well trodden path but looking at the tube choices some make given the use of the bike and the size/weight of the rider makes me think it might not be.

The proper BB stiffness is generally pretty easy to get with the chainstay choice. Torsional stiffness is something many don’t talk about but it’s the key to get good handling. If the frame twists too much it will handle like crap…there’s little downside to having the frame stiffer than need be in torsion but if it’s been made too stiff there’s a good chance that the frame is heavier than it should be or that the ride will be harsh.

Braking stiffness is super important. If the fork is too soft and you grab a big handful of brake life can get overly exciting with chatter and/or funny handling due to the variable rake from flexing rearward.



- level three - this one is hugely subjective. Does the bike feel good to ride? Is it fun? Does it feel secure and stable while not being dead or boring in feel? Is the bike quiet feeling to your body and to the ear. Does the design encourage the me to take the long way home so that they get a bit more time on it? Does it have that wonderful ’snap’ when you get up to crest a roller out of the saddle. Does the steering feel right both in and out of the saddle? Can you sit up and open a Clif bar? Does the bike steer and handle intuitively on the surface it’s designed for? And do you find that when you end the ride that you lean it against the wall and as you walk away can’t resist turning back and taking one last look at it before food and a shower.



In the end I aim to please myself. If after all this time I like the bike that’s saying something. There’s been a crap-load of bikes over the past 30 years that I wanted to love but didn’t. It’s a bummer in that moment but it’s also a wonderful learning opportunity. But at the end of the day I think that if I like it that others will too. They might not know why and that matters little really. I know that I can design a bike for someone else that is a different size and weight than I am by picking the right tube….and when combined with the right fit and feel I feel confident that they will enjoy their bike as I enjoy mine.


I hope that makes sense.

Dave

[jaewoo.kim.88]

Timeless (stainless steel) and modern (wide tires, 1x gearing) rim-brake (yes!) do-it-all bike - love it.